good gyms also don't. you went to a chain that uses sleazy tactics. they probably won't even allow you to pay month by month but only via 12mo plans.

the usa is the same in big cities. apart from ymca, no other big chain will allow you to not incur a 12mo obligation which they will take you to collections.

hence they need all data, already planning the collections step.

just find a better gym, or accept you are entering a conplex financial contract. that's what giving you cpf/ssn means and serve as a signal of.